Microbes for ammonia removal

Ammonia - a challenge for most wastewater plants

Ammonia is present in most wastewater streams. In municipal plants, urea hydrolysis and the degradation of organic nitrogen compounds generate ammonium ions. In food processing wastewater plants, protein-rich wastewaters contain high concentrations of ammonium ions. In refinery wastewater, ammonium ions are often caused by the hydrolysis of amines used to inhibit corrosion in crude. Effective ammonia removal, or nitrification, is essential for wastewater treatment plants. Without it, they’re at risk of non-compliance and ammonia-related permit violations.

Nitrification is a sensitive process

Ammonia removal is a two-step biological process involving aerobic nitrifying bacteria. In the first step, ammonia-oxidizing bacteria (AOB) oxidize ammonium ions NH₄⁺ to nitrite NO₂^-. In the second step, nitrite-oxidizing bacteria (NOB) oxidize nitrite to nitrate NO₃^-. However, these nitrifying bacteria grow very slowly. That makes nitrification a sensitive process. Environmental factors, toxicity, solids washout and loading variation can all easily interrupt nitrification in your plant. Recovery from upsets can also be slower in nitrification than in other wastewater treatment processes.